One of the problems with building the world's largest and most powerful gas turbine is that you need to build a test bed to match. Having invested US$1 billion in its 500,000 bhp 9HA Harriet gas turbine, GE had to fork over another US$185 million to build a full-load test bed at GE Power & Water in Greenville, South Carolina that can handle the grid-busting output of Harriet.
The latest of GE’s H-class turbines, when partnered with a steam generator Harriet can run a 600 megawatt steam power plant capable of supplying 600,000 homes, burns a variety of natural gases from shale gas to liquid natural gas, and instead of generating electricity, blasts out hot air at speeds of a Category 5 hurricane that could fill a Goodyear blimp in about 10 seconds.
To achieve this, Harriet has superalloy monocrystal turbine blades with thermal barrier coatings capable of withstanding 2,900° F (1,600° C). It has variable stator vanes originally developed for supersonic jet engines that direct the airflow, and a modular design with blades that can be replaced individually. In addition, it's designed for automated operation, has a combined cycle efficiency of over 61 percent, and low emissions.
GE says that field testing such a monster machine has its limitations. Not only do field tests lack the extremes that the turbine might encounter, but it limits the data collected. Another problem is that the power output of Harriet can destabilize or damage the power grid during extreme testing, so it needs to be isolated. That's where the Greenville rig comes in.
The new turbine test bed not only has its own gasworks with 180,000 gallons (681,000 L) of liquefied natural gas, it also boasts North America’s largest railroad turntable to move Harriet about. According to GE, the test bed can simulate altitude and temperature conditions from hot deserts to frigid mountains.
"Here we can really see what it’s made of," says, Eric King, GE’s man in charge of the test bed. "In field testing, we measure data and extrapolate. With this test stand, we measure data and then verify it."
Testing on the French-made Harriet began in April of last year and went on for three months. During this time, engineers simulated normal operations, tested, fuel and load flexibility, and subjected the turbine to overloading outside specifications with extreme events, such as oversupplying the grid with power.
While this was going on, 5,000 instruments and sensors on Harriet and another 2,000 on the test bed collected 5 TB of data and ran it through a bespoke software suite. GE says that this shaved a year off the development cycle, and that the data will be used to aid future development, as well as fine tune the turbine, of which 15 are on order in the United States, Europe, and Japan.
The video below discusses the 9HA Harriet and its testing.
Source: GE
I do hope they are making use of the massive amounts of very hot gas, such as for supplying hot water for domestic use, if the powerplant is actually situated near any towns or cities.
Just curious, but does this type of powerplant actually produce a thrust, similar to a jet engine?
Google says it was built at GE’s Manufacturing Facility in Belfort, France. It might have been operationally tested before shipping, but it's the largest ever built so I doubt it could be fully tested without building a new test rig somewhere in the world. It's hard to scale, but this is a very large object. In the first picture of the image gallery, notice there are 4 people standing in and around the housing.
"Mention is made of the possibility of overloading the grid. Surely the output capacity is known? "
The output is certainly know, but the amount of grid load can not be. It would be hard to test full load and fault conditions unless you know for certain that the grid can take all of that energy. If I understand correctly, the speed of the turbine is fixed to synchronize with the grid, the amount of torque is the variable?
"I do hope they are making use of the massive amounts of very hot gas, such as for supplying hot water for domestic use"
Even better than hot water, that's the difference between simple cycle and combined cycle. The high quality waste heat is used to make steam for a second turbine.
It would be difficult and costly to provide hot water for domestic use. The plant output varies, therefore the amount of waste heat also varies. Meaning the domestic load would need to vary along with plant output, and always be able to have the capacity to cool the plant. A vary unlikely situation in the real world.
"Just curious, but does this type of powerplant actually produce a thrust, similar to a jet engine? "
The article says the volume of air coming out is enormous. I suspect the exhaust housing is designed to minimize thrust, notice how the output flairs open? A jet's exhaust constricts down to increase flow velocity, providing greater thrust.
This is a very impressive feat by the GE teams, both design and testing.
"Why build a machine that is destined to be a logistics nightmare purely because of its size, when a dozen or so smaller proven turbines could do the job" In Gas Turbines, size is power and efficiency. Double the size of a turbine and you increase the flow by 4 times and the power increases with flow. Other things like clearances and other loses don't go up as much so you get higher efficiency. The power plant actually gets much more complicated with more units so fewer is better.
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I believe that turbines this size and even larger ones which will follow will be used to maintain Large Capacity Grid Storage batteries in various locations across the USA and make sharing Energy an even better deal, once the Grid gets upgraded.